79

79 is the natural number that comes after 78 and before 80. In Roman numerals it is LXXIX. In base-2 it is 1001111, in base-8 it is 117, and in base-16 it is 4F. It is a prime number, the 22nd prime, and an odd two-digit number.

As a prime, 79 has no positive divisors other than 1 and itself. It is not divisible by 2, 3, 5, or 7. Its primality places it among the relatively small set of numbers that are divisible only by 1 and the number itself.

The element with atomic number 79 is gold (chemical symbol Au). Gold is a dense, soft metal with high electrical conductivity and excellent corrosion resistance. It occurs in native form in nature and has long been mined for use in jewelry, electronics, and finance. Gold alloys and refined forms are widely traded and stored as a monetary asset. Its melting point is 1064 degrees Celsius and its density is about 19.32 g/cm³. The most abundant stable isotope is Au-197.

The year 79 CE is notable in ancient history for the eruption of Mount Vesuvius, which burying the Roman cities of Pompeii and Herculaneum in volcanic ash. Contemporary accounts by Pliny the Younger describe the eruption and its impact on the Roman world.

In computing, the decimal code 79 corresponds to the uppercase letter O in ASCII, reflecting its use as a character encoding value in text data.